On pg 39, the old man makes it clear that talking is something that is sort of frowned upon by fishers when out at sea. however the old man seems to no longer have any shame in talking to himself while fishing. This could be what happened to Hemingway during the end of his life. Maybe he began to do thing that were frowned upon, but he did not care.

On pg 39,"It was considered a virtue not to talk unnecessarily at sea and the old man had always considered it so and respected it. But now he said his thoughts aloud many times since there was no one that they could annoy"

Virtue = conformity of one's life and conduct to moral and ethical principles; uprightness; rectitude. (dictionary.com)

Throughout Hemingway's writing career, one could say that he kept with what people would expect of him. The word "unnecessary" could refer to Hemingway's writing style of keeping it simple; that he doesn't add "unnecessary" parts to his story. I feel that Hemingway is reaching further inside himself in order to write something and if that means going against his previous "virtue", then he would do it because he feels no longer restricted of others expectations. (sort of venturing out new ways of writing?)

OR possibly...

"he said his thoughts aloud...there was no one that they could annoy"

My initial thought was that Hemingway felt that he was better than most people. It's kind of hard to hold an intellectual conservation with someone who is ignorant, and to the person on the receiving end, it would be annoying because they don't understand the words being spoken.

I do agree with Kayla that over time Hemingway just didn't care anymore about other people's opinions.